Various electronic device, for example in general, lamps such as a head lamp and a tail lamp, and motors such as a starter motor and a motor for air conditioners, are mounted on a vehicle as a moving object.
The vehicle arranges an electric junction box in a suitable place so as to supply various electronic devices with electric power. The electric junction box is constructed by assembling various type electric circuits of a lot of fuses and relays.
Incidentally, the electric junction box has a fuse, a relay, a bus bar and the like. So, the electric junction box is referred to as a fuse block, a relay box, or a junction block. In this description, the fuse block, the relay box and the junction block are collectively called the electric junction box hereafter.
A conventional electric junction box has a box main body, and an electric power distribution unit received in the box main body. The box main body is formed in a box-shape, and has a lower cover and an upper cover. The lower and upper covers are installed each other, and receive the electric power distribution unit after being attached to each other. Furthermore, the lower and upper covers are made of insulating synthetic resin, and injection-molded. One of the lower and upper covers has a locking portion, and the other has a locking receiving portion.
The electric power distribution unit has a printed-wiring board, a plurality of connectors mounted on the printed-wiring board, a fuse holding portion for maintaining the connectors mounted on the printed-wiring board, and a plurality of relays mounted on the printed-wiring board. A conductor pattern of the printed-wiring board is electrically connected to each terminal of the connector, the fuse, and the relay based on a predetermined pattern.
The connector is inserted into a through hole penetrating through the outer wall of the box main body, and exposed outside of the box main body. At least one of the plurality of connectors is fitted in a connector attached to a terminal of a supply cable connected to an electric power supply of a battery or electric generator mounted on a vehicle. The other connectors are fitted in a connector attached to a terminal of a wiring harness connected to various electric devices mounted on the vehicle.
The fuse holding portion is inserted into the through hole penetrating through the outer wall of the box main body, and exposed outside of the box main body. Furthermore, the fuse holding portion holds a plurality of fuses. The relay is mounted on the printed-wiring board, and received in the box main body.
The above conventional electric junction box divides electric power supplied from the connector connected to the electric power supply with the conductor pattern of the printed-wiring board, and distributes the electric power to various electric devices through an electric wire of the wiring harness after the electric power is supplied to the fuse and the relay.
The above conventional electric junction box assembles the upper and lower covers to each other by fitting the locking portion to the locking receiving portion. In order to smoothly fit the locking portion to the locking receiving portion, the conventional electric junction box has a moderate space between them. For this reason, in the conventional electric junction box, the covers are moved by vibration when running a vehicle, and they collide and separate with each other repeatedly. As a result, abnormal noise generates.
Accordingly, an object of the present invention is to provide a box main body which can smoothly attach the cover members, and prevent abnormal noise.